extra money in keeping it postive

Even though I am retired from my regular job, and receiving my pension, I am also working part time. I am on call - filling in for someone when she is not able to work. She's had various health issues in the past three years, so it's a NICE income.

My problem is that I spend it... over and over again. I find that my mindset is that I have extra money... so... I can buy more clothing, more books, eat in restaurants more often, buy theater tickets, etc. I just have to make sure that I am not spending more than I earn.

I have the thought that oh, I'll use this for my next vacation... and for shopping... and for food. Yes, the income is good, but I have to clear the idea out of my head that it's unlimited...